Improved electro-magnetic fire-alarm apparatus



M; FARMER. Fire- Alar TelegraphIA A Ne. 23,060. Patented Feb. 2.2.1859.`

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UNITED AST1-tras PATENT OFFICE.

MOSES G. FARMER, OF SALEM, MASSACHUSETTS, ASSIGNOR T() WM. F. CHANNING.

IMPROVED ELECTRO-MAGNETIC FIRE-ALARM APPARATUS.

Specification forming part of Letters Patent No. 23,060, dated February 22, l859.

To all whom it may concern:

Be it known that I, Moses G. FARMER, of Salem, in the county of Essex in the State of Massachusetts, have invented a new and Improved Town Fire-Alarm System; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawing, and to the letters of reference marked thereon.

The nature of my improvement consists in combining two or more key-boards or tire-alarm strikers with one or more electro-telegraphic striking-machines or alarm apparatus in the same closed electric circuit or in dependent closed electric circuits within `the area of a town or municipality.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation.

In the fire-alarm telegraph now in operation in the cities ofBoston and of St. Louis, for which Letters Patent were granted to me in connection with Wm. F. Channing, of Boston, on the 19th of May, 1857, and to which reference is here made, a signal-circuit, so called, is employed to convey the information of a fire from any part of the area of a city to its central telegraphic station, where it is received by an operator. Another circuit, called an alarmcircuit,77 connects the same central station with telegraphic striking or alarm machinery in the public-bell towers. At the center station is placed a district key-board or other apparatus connected with the alarm-circuit for the purpose of completing and breaking the circuit at suitable intervals, so as to strike a definite alarm upon the public bells. The operator with this machinery is enabled to receive iuformation of the existence and locality of a fire by means of the signal-circuit, and then by an act of intelligence and volition to strike a corresponding deflnite alarm on the public bells in the bell-towers by means of the district keyboard or other apparatus placed in the alarm circuit, so called. This system requires the expense of a central office and of an operator always on the spot.

By my present improvement I dispense, in the case of smaller towns or cities, with the central oilice and unite the functions of both the signal and alarm circuits in one fire-alarm circuit provided with suitable apparatus.

In the drawing the divisions I II III, col ored respectively red, blue, and yellow, represent the ground plan of a town divided into three tire districts or wards. f The lire-alarm circuit consists of telegraphwires supported on posts or buildings and duly insulated in the ordinary way. This is represented by the green lines a a a, continuous or dotted.

Three alarm-towers are represented by the blocks A A' A, containing electro-magnets b b b, or their equivalents, which are included in the iirm-alarm circuit a a a. These electro-magnets are here described and understood as forming part of my electromagnetic escapement and apparatus, called improvement in magnetic alarm-bells,77 for which Letters Patent of the United States were granted me May 4, 1852, or as forming part of any other suitable device for liberating alarm machinery in the alarm-towers A A A; but such apparatus or device must be arranged so as to work in a closed circuit.

It is well understood that the armature of an electro-magnet, in its reciprocating motion, is drawn toward lor held to the magnet when the electric circuit is closed, and that it is drawn back from the magnet by the reacting power of a spring when the electriccircuit is broken. In a closed-circuitarrangementthose motions are accomplished by the reaction of the spring which in au open-circuitarrangement would be accomplished hy the direct electro-magnetic force.

In my electro-magnetic escapement referred to above, in an open-circuit arrangement the weighted arm is tripped by the withdrawal of the armature by the direct force 0E an electromagnet. In a closed-circuit arrangement, in an equivalent action, the weighted arm is tripped by the withdrawalof the armature from the electro-magnet by the reactive force of a spring when the circuit is interrupted. The two methods are equivalent; but I describe the closed-circuit arrangement here so that any person skilled in the art may construct the whole of my system from this specification and the references herein made.

`Four district key-boards or strikers are represented-in an elementary form at B C D E. These consist of closed-circuit wheels c d e j', on which springs g always bear, completing the fire-alarm circuit, except when one of the ivory segmentsh lo lpasses under one of the springs g in the course of the revolution of the circuitwheel, breaking the circuit at such times and giving an automatic signal, according to their number and arrangement. For instance, in a key-board two such circuit-wheels might be combined, on causing one of which to revolve the district number III might be automatically signalized, and on causing the other of which to revolve an arbitrary signal-such as I, II might be automatically given, to signify that the nre was all out.

The circuit-wheels in the drawing are represented with weighted handles m, whichkeep them in such position that the circuit is always closed when they are at rest. The circuit-wheels can be revolved by the hand applied to the handles m but for actual service the circuitwheel is carried by clock-work with greater regularity than it can be moved by hand, and will be liberated by depressing a key.

The fire-alarm circuit is made to include the key-board E by connecting one wire, a', of the circuit with the base of the spring y and the other wire, a", ofthe circuit with the stud sup'- porting the circuit-wheel f, and it is made to include the other key-boards in a similar way. It passes also through all the electro-magnets b b bin the bell-towers and connects with the two poles n o of the battery, and thus makes a continuous communication or circuit through the battery and the bell-towers and key-board ystations contained in the system.

The number of ivory segments on each eircuit-wheel will correspond with the number of the ward or district of the town in which it is placed, or to the number designating the keyboard itself if it is designed to strike th at number on the bells.

In the drawing, the circuit-wheel c of the key-boardB, placed in the red district, marked I,has one ivory segment,h. The circuit-wheels d ein the key-boards C D, placed in the blue district, marked II, have each two ivory segments, t' 'i 7c 7c. The circuit-wheel f of the keyboard E, in the yellow district, marked III, has three ivory segments, l l l. Several such keyboards may be placed in the same tire-alarm circuit. They will ordinarily be placed inside ot buildings, such as police-stations, apothecaries7 shops, or perhaps alarm-towers.v

The key-boards may be inclosed in a castiron box with a door which may be locked.

As an additional precaution against an accidentalfinterruption of the circuit from imperfect contact between the circuit-wheel d and the spring K, the shutting of the door may be made to close the circuit by pressing a spring connected with one wire of the circuit against an insulated anvil connected with the other wire of the circuit.

A galvanic battery, F, or some other source of electricity, is included in some part of the circuit. It may be placed conveniently in one of the buildings used in the system, either as a key-board station or as an alarm-station, or as both. The battery Fconsists of a copper plate, a, and a zinc plate, o, excited by an interposed piece of cotton-flannel moistened withl dilute acid.

In practical operation aform of constant galvanic battery will be used which will need attention only at considerable intervals of time,

and a sufficient number of pairs will be used to overcome the resistance of the conductors of the circuit.

Having thus described the several parts of my improvement, I will now describe them in their mutual dependence and operation.

The'lbattery Fbeing placed in action, a closed circuit is established through the tire-alarmcircuit wires a, the weighted handles m keeping the circuit closed through the circuitwheels c d e f. The electro-magnets e e c" in the alarm towers are thus permanently charged with magnetism while the system is at rest. An armature placed before the poles of each of the electro -magnets is thus permanently held near to or in contact with the electro magnet while the circuit remains closed, and if such armatures are suitablyconnected with electro -magnetic-alarm machinery in each of the alarm-towers, such machinery will be held at rest while the circuit remains closed and attract their armatures, and thereby detain the alarm machinery from acting. If a fire occurs now in district III, near key-board E, the circuit-wheel f is set in motion by an authorized person. As the ivory segments l l Z pass under the spring g the lirealarm circuit is momentarily interrupted, the armatures in the alarm-towers are released, and the alarm machinery gives one signal for each interruption. If bells are used, the bells in the three towers A A' A each strike three blows and make a suitable interval between the series each time that the circuit-wheel f is revolved. A public alarm of district III is thus given instantaneously all over the town.

Instead of an electro-magnet, an armature in the alarm-stations, an axial bar moving in a coil, or any other equivalent electro-magnetic device may be used.

In the circuit-wheels f any non-conducting substance may replace the ivory segments, or segments may simply be cut out of the circuit-wheels at corresponding places, or any otherwise equivalent form of circuitwheel used.

If a town is large, and it is desirable therefore to divide the tire-alarm circuit into two or more circuits, this can be done by making them mutually dependent, so that operating one will operate all the others. In this case there must be a battery in each circuit and a relay at the point of connection between two mutually-dependent circuits, constructed so as to operate equally well both ways, in a more electro-telegraphc-alarm machines, in

manner similar to that for which Letters Patent of the United States were granted to me on 29th day of January, 1856.

What I claim as my invention, and desire to secure by Letters Patent, is-- The combination of two or more key-boards or fire-alarm strikers, constructed and operating substantially as described, with one or the same closed electric circuit or in dependent closed electric circuits by means of a mechanism that will make and break a circuit, as herein shown and described.

MOSES G. FARMER. Witnesses:

THos. R. ROACH, P. E. TEISGHEMAGHER. 

